The invention relates to a hand brace for immobilizing and adjustably positioning one or more digits of the hand, and more specifically, to a brace having a flexible sheet member, at least one adjustable stabilizing member that is sufficiently rigid to maintain joints at a desired angle of flexion, and a semi-rigid member positioned against the flexible sheet member for protecting and supporting joints of the hand. Advantageously the invention immobilizes the hand such that the fourth and fifth metacarpophalangeal joints of the hand are positioned at a desired angle of flexion and the fourth and fifth interphalangeal joints of the hand are positioned at full extension.
As known by boxers or participants in combat athletics, a “boxer's fracture” commonly refers to a fracture at the neck of the fifth metacarpal bone (i.e., the little finger or pinky finger) which is the most lateral metacarpal of a human hand. Except in unique instances, a human hand is comprised of four fingers and a thumb. Beginning with the closest finger to the thumb (i.e., first digit), each finger is colloquially referred to as follows: index finger or forefinger (i.e., second digit), middle finger (i.e., third digit), ring finger (i.e., fourth digit), and little finger (i.e., fifth digit).
The hand is also comprised of bones and joints that form the fingers, thumb, and palm. Beginning at the wrist, the bones of the hand include carpals, metacarpals, proximal phalanges, intermediate phalanges, and distal phalanges. The joints of the hand include, among others, the metacarpophalangeal and interphalangeal joints.
The metacarpophalangeal joints are located between the rounded heads of the metacarpals and the shallow cavities on the proximal ends of the first or proximal phalanges of the fingers with the exception of the thumb.
The interphalangeal joints are hinge-joints of the phalanges of the hand. Absent the thumb, each finger of the human hand has two sets of interphalangeal joints, namely, the proximal interphalangeal joints and the distal interphalangeal joints. The proximal interphalangeal joints are located between the first (or proximal) phalanges and second (or intermediate) phalanges. The distal interphalangeal joints are located between the second phalange and third (distal) phalange.
A boxer's fracture is usually caused by the impact of a clenched first with a skull or a hard, immovable object, such as a wall or a door. During a boxer's swing, for example, the knuckle or metacarpophalangeal joint of the little finger (i.e., fifth metacarpal) tends to lead the rest of the knuckles in a hard punch. Upon impact, the knuckle compresses and snaps or fractures the distal end of the metacarpal.
Such fractures are often angulated, and if severely so, the fracture requires pins and realignment as well as a splint. Total healing time typically does not exceed more than 12 weeks. Soft casts or splints are preferred over hard casts because the splint or brace can be removed for brief periods of time to allow for bathing and to avoid skin irritation. The typical rehabilitation period is approximately four months with adequate therapy.
The preferred positioning of the hand in a splint or brace is referred as the “intrinsic plus position.” In this position, the hand can be immobilized for long periods of time and joint stiffness is reduced as compared to alternative positioning of the digits. In the intrinsic plus position, the metacarpophalangeal joints are flexed at 60 to 70 degrees and the interphalangeal joints are fully extended. The wrist is positioned in extension at 10 degrees less than maximal.
In the intrinsic plus position, the metacarpophalangeal joints are in flexion and the interphalangeal joints are in full extension. “Flexion” of the fingers and joints refers to a bending movement that decreases the angle between two parts of, for example, the finger. “Extension” of the fingers and joints, the opposite of flexion, refers to a straightening movement that increases the angle between the body parts.
It is understood that flexion of the fingers promotes recovery of the metacarpophalangeal joints, and extension of the fingers promotes recovery of the interphalangeal joints, based on differences in the shape of the metacarpal head, volar plate, and collateral ligament anatomy of the hand and wrist. The metacarpal head is uniquely shaped in that it is ovoid in the sagittal plane, and widens from the dorsal to the volar or palmar dimension. The collateral ligaments are eccentrically mounted dorsal to the axis of rotation of the metacarpophalangeal joint. This anatomy causes variable degrees of tightness on the collateral ligaments based on the position of the joint by a cam-like effect. When the joint is in extension, the collateral ligaments are lax. When the joint is in flexion, the collateral ligaments span a greater distance and are tight.
In addition, the metacarpophalangeal joint is also curved in two planes to permit abduction (i.e., a motion that pulls the fingers away from the midline of the body as in spreading the digits apart and away from the centerline of the hand), adduction (i.e., a motion that pulls the fingers towards the midline of the body as in closing the digits together), and rotation, as well as flexion and extension in an abbreviated ball-and-socket configuration. In flexion, bone surface area contact is greater than in extension, thereby producing a more stable joint.
Accordingly, the hands, and specifically the metacarpophalangeal joints are particularly vulnerable to fractures. Athletes experiencing a boxer's fracture often utilize some form of hand and wrist support during recovery. Many athletes rely upon a splint and taping to provide support during recovery. Although known splints and taping stabilize the metacarpophalangeal joints a number of drawbacks exist. For example, known splints may restrict all motion of the hand and fingers, both desirable and undesirable. Further, known splints fail to simultaneously provide sufficient support of the hand and fingers in the intrinsic plus position wherein metacarpophalangeal joints are flexed between about 60 to 70 degrees, and the interphalangeal joints may be fully extended, while providing support and protection of one or more metacarpals. The restrictive characteristics of known splints thus hinder proper recovery of boxer fractures.